Inner tegument proteins of Herpes Simplex Virus are sufficient for intracellular capsid motility in neurons but not for axonal targeting.
Inner tegument proteins of Herpes Simplex Virus are sufficient for intracellular capsid motility in neurons but not for axonal targeting.
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DOI：
10.1371/journal.ppat.1006813
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发表时间：
2017-12
期刊：
影响因子：
6.7
通讯作者：
Sodeik B
中科院分区：
文献类型：
--
作者：
Buch A;Müller O;Ivanova L;Döhner K;Bialy D;Bosse JB;Pohlmann A;Binz A;Hegemann M;Nagel CH;Koltzenburg M;Viejo-Borbolla A;Rosenhahn B;Bauerfeind R;Sodeik B
在神经元的潜伏期和裂解性感染期间重新激活，α疱疹病毒组装胞质衣壳、与包膜相关的衣壳以及含有完全包膜衣壳的运输囊泡。单纯疱疹病毒（HSV）的衣壳包裹是否是在轴突靶向之前或之后在体细胞中完成，以及来自胚胎或成年宿主的神经元中的机制是否相同，仍存在争议。我们使用衣壳包膜受损的 HSV 突变体来测试微管介导的衣壳运输所需的内皮蛋白 pUL36 或 pUL37 是否足以在成年小鼠背根神经节衍生的神经元中实现轴突衣壳靶向。这些神经元被感染了HSV1-ΔUL20，其衣壳招募了pUL36和pUL37，感染了HSV1-ΔUL37，其衣壳仅与pUL36结合，或者感染了HSV1-ΔUL36，其组装了缺乏这两种蛋白质的衣壳。 HSV1-ΔUL20的衣壳沿着上皮细胞和神经元体细胞中的微管积极运输，而HSV1-ΔUL36和-ΔUL37的衣壳只能在细胞质中扩散。采用一种新颖的图像分析算法来量化衣壳对轴突的靶向，我们发现只有少数 HSV1-ΔUL20 衣壳进入轴突，而运输 gD 的囊泡有效地利用轴突运输，且独立于 pUL36、pUL37 或 pUL20。我们的数据表明，由 pUL36 和 pUL37 介导的神经元胞体中的衣壳运动不足以将衣壳靶向轴突，并表明在单纯疱疹病毒靶向轴突并从神经元扩散到邻近细胞之前，需要在胞体中完成衣壳包封。人类和动物α疱疹病毒在周围神经系统的神经元中建立终生潜伏感染，并在初次感染以及从潜伏状态重新激活后引起许多疾病。高度流行的人类单纯疱疹病毒 HSV-1 和 HSV-2 会导致面部和生殖器疱疹、可能致盲的眼部感染以及危及生命的脑炎和脑膜炎。在这里，我们询问这些病毒如何克服从神经元体细胞到轴突的攻击瓶颈。我们的数据表明，只有含有完全成熟病毒颗粒的运输囊泡才能进入轴突，将感染传播到大脑或周围器官。我们的数据表明，运输囊泡的限制膜必须暴露病毒或宿主受体，以招募轴突运输所需的微管马达。抑制运输囊泡表面的此类病毒因子可能会提供新的治疗方法来防止α疱疹病毒在神经系统中的传播。
Upon reactivation from latency and during lytic infections in neurons, alphaherpesviruses assemble cytosolic capsids, capsids associated with enveloping membranes, and transport vesicles harboring fully enveloped capsids. It is debated whether capsid envelopment of herpes simplex virus (HSV) is completed in the soma prior to axonal targeting or later, and whether the mechanisms are the same in neurons derived from embryos or from adult hosts. We used HSV mutants impaired in capsid envelopment to test whether the inner tegument proteins pUL36 or pUL37 necessary for microtubule-mediated capsid transport were sufficient for axonal capsid targeting in neurons derived from the dorsal root ganglia of adult mice. Such neurons were infected with HSV1-ΔUL20 whose capsids recruited pUL36 and pUL37, with HSV1-ΔUL37 whose capsids associate only with pUL36, or with HSV1-ΔUL36 that assembles capsids lacking both proteins. While capsids of HSV1-ΔUL20 were actively transported along microtubules in epithelial cells and in the somata of neurons, those of HSV1-ΔUL36 and -ΔUL37 could only diffuse in the cytoplasm. Employing a novel image analysis algorithm to quantify capsid targeting to axons, we show that only a few capsids of HSV1-ΔUL20 entered axons, while vesicles transporting gD utilized axonal transport efficiently and independently of pUL36, pUL37, or pUL20. Our data indicate that capsid motility in the somata of neurons mediated by pUL36 and pUL37 does not suffice for targeting capsids to axons, and suggest that capsid envelopment needs to be completed in the soma prior to targeting of herpes simplex virus to the axons, and to spreading from neurons to neighboring cells. Human and animal alphaherpesviruses establish lifelong latent infections in neurons of the peripheral nervous system and cause many diseases upon primary infection as well as following reactivation from latency. The highly prevalent human herpes simplex viruses HSV-1 and HSV-2 are responsible for facial and genital herpes, potentially blinding eye infections, and life-threatening encephalitis and meningitis. Here, we asked how these viruses master the bottleneck of being targeted from the neuronal somata to the axons. Our data suggest that only transport vesicles harboring fully matured virus particles can enter axons for spreading infection to the brain or the peripheral organs. Our data imply that the limiting membrane of the transport vesicles must expose viral or host receptors to recruit the microtubule motors required for axonal transport. Inhibiting such viral factors on the surface of the transport vesicles might provide novel therapeutic approaches to prevent the spread of alphaherpesviruses in the nervous system.